Neuronal Deficiency of Cytochrome c Oxidase Engineered by Mitochondrial DNA Editing Recapitulates Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is categorized into 10% familial and 90% sporadic cases. While the space of 10% familial ALS is crowded with mutations in many genes of diverse functions, most ALS-associated mutations could not faithfully recapitulate the disease phenotype in animal models. Remarkably, nearly half of sporadic ALS patients exhibit defective mitochondrial respiratory complex ? (C?). To establish the causal role of defective C? in inducing ALS, we employed TALE-based mtDNA editing to mimic ALS-linked mutations in C? compared to other respiratory complexes in rat neurons and demonstrated that mutations exclusively introduced to mtDNA-encoded C? subunits are sufficient to cause a full spectrum of ALS-like phenotypes, including selective motor neuron loss, SOD1 overexpression and cytosolic TDP-43 aggregation. These findings reveal a broad basis for sporadic ALS, provide critical insights into the selective motor neuron vulnerability, and present a faithful animal model for advancing ALS therapy. Overall design: To investigate the effects of mitochondrial respiratory complex ? deficiency in rat neurons , the spinal cord and brain of WT, COX?NeuN-Cre rats, were dissected , and the RNA was isolated to perform the bulk RNA-sequencing study (n=4/6 per group).